The present invention relates to a medical treatment instrument such as scissor forceps used for coagulating and cutting blood vessels or the like by inserting it into the patient's body cavity.
As a medical treatment instrument inserted into the patient's body, for example, a pair of electric heating type scissors is disclosed in German Patent DE 297 02 608 U1. This pair of electric heating type scissors is provided with two scissor constituent members rotatably coupled with each other around a rotating movement pin. A layer capable of electric heating is provided at a part of a dissection region disposed at the tip of these scissor constituent members.
In the electric heating type scissors disclosed in German Patent DE 297 02 608 U1, the two scissor constituent members are formed by relatively sharp cutting blades with thin plate thickness, respectively. Thus, when a patient's body tissue such as blood vessel is grasped between the two scissor constituent members, a contact area between these two scissor constituent members and the patient's body tissue is reduced. As a result, there is a problem that the patient's body tissue such as blood vessel cannot be sufficiently compressed between the two scissor constituent members, and the patient's body tissue such as blood vessel cannot be thermally coagulated.
In addition, in U.S. Pat. No. 5,342,381, there is disclosed a treatment instrument in which a treatment portion comprising a pair of treatment members capable of being opened and closed is arranged at the tip of the main body of the treatment instrument, and a frontal operating portion for opening/closing a pair of treatment members is arranged at the proximal end of the main body of the treatment instrument. In this treatment instrument, a grasp portion for grasping patient's body tissues is arranged at the tip side of the treatment section, and a dissection scissors section is arranged at the rear end of this grasp portion. In this treatment instrument, a bipolar high-frequency current is supplied to the grasp portion during in use; the patient's body tissue grasped by the grasp portion is coagulated by this high-frequency current, and then, a coagulation section of this patient's body tissue is cut at the scissors section.
In addition, the treatment instrument disclosed in U.S. Pat. No. 5,342,381 is configured to supply a bipolar high-frequency current to the grasp portion at the tip side of the treatment section, so that a portion of the scissors section at the rear end of the grasp portion cannot be made of metal. Therefore, in the treatment instrument disclosed in U.S. Pat. No. 5,342,381, the scissors portion of the treatment section is composed of an insulator consisting of ceramics. However, thus, there is a problem that, when a ceramic based scissors portion is used, the dissection capability is gradually degraded due to a friction between slide portions of the scissors portion during in use.